Machine for high speed, extremely precise mass working of pieces having small dimensions and complex forms, in particular of metallic small articles

ABSTRACT

Small metallic workpieces are subjected to a sequence of work operations at a surrounding series of work stations, by mounting them on a rotary carrier that rotates intermittently through predetermined equal angular increments successively to dispose each workpiece at each work station.

Unit States Patent Bertoglio [4 1 Sept. 12, 1972 [54] MACHINE FOR HIGHSPEED, EXTREMELY PRECISE MASS WORKING OF PIECES HAVING SMALL DIMENSIONSAND COMPLEX FORMS, IN PARTICULAR OF METALLIC SMALL ARTICLES [72]Inventor: Guido Bertoglio, Viganello, Switzerland [73] Assignee: S. A.Albe, Agno, Switzerland [22] Filed: July 31, 1970 [21] Appl. No: 59,908

[30] Foreign Application Priority Data April 10, 1970 Switzerland..5406/7O [52] US. Cl. ..29/38 C, 408/38, 408/45, 408/71 [51] Int. Cl..B23b 39/20, B23b 39/22 [58] Field of Search ..29/38 C; 408/71, 45, 38

[56] References Cited UNITED STATES PATENTS 2,803,840 8/1957 McShirley..408/38 X Primary Examiner-Francis S. Husar Attorney-Young & Thompson[5 7 ABSTRACT Small metallic workpieces are subjected to a sequence of.work operations at a surrounding series of work stations, by mountingthem on a rotary carrier that rotates intermittently throughpredetermined equal angular increments successively to dispose eachworkpiece at each work station.

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INVENTOR Gu/po $527064 /0 PATENTEDSEP 12 1912 3,5 9 955 sum 15 or 16INVENTOR BY 7 MM PATENTEDSEP 12 m: 3.689 965 SHEET IBM 16 INVENTOR 60/00 fifzTdL /0 ATTORNEYS MACHINE FOR HIGH SPEED, EXTREMELY PRECISE MASSWORKING OF PIECES HAVING SMALL DIMENSIONS AND COMPLEX FORMS, INPARTICULAR OF METALLIC SMALL ARTICLES The present invention relates to amachine for the high speed, mass production with extreme precision ofsmall pieces with complex forms such as: electric contacts, screws,horological pieces, carburettornozzles, breaker contacts, special piecesfor cameras and delicate equipment .or apparatuses and in generalmetallic small articles.

There exist at present several automatic machines for the rapidmanufacturing of metallic s'mall articles such as ball point pens,screws and the like (see for instance the Swiss Patent Nos. 337,053 and358,003). These machines are however expressly designed and constructedto manufacture a single type of article, for instance either ball pointpens or electric plugs or screws so that, should it be wanted tomanufacture with a given machine an article that is different from theone the machine is designed for, it would-be necessary to change a greatmany parts of said machine.

The machine according to the present invention, on the contrary, withoutrequiring substantial changes of production accessories, may be rapidlyadapted to produce with very high precision (tolerance of the order ofthe microns) articles of very small dimensions and complicated formswhich are different one from the other. Furthermore, the machine of theinvention is so devised as to make it possible to change, with greatrapidity and within a wide range, the working speed while maintainingconstant the speed at which the articles are fed from oneworking-station to the next one. This feature is responsible for aconsiderable increase in the production and, as a consequence thereof,for a and being fixable to the outer stationary frame coaxial to thecentral shaft;

by means which exactly fix with great rigidity the position reached bythe turntable at each working station before starting the workoperation, said fixing being obtained by engaging and firmly holdingsaid stationary inner sleeve as well as said external stationary frame;

by secondary members which displace angularly to itself the axis of eachworkpiece-carrying di'sc so as to bring the same into the right workingposition and means to fix the same in exact position before starting theworking process; said discs being so shaped as to permit working withchucks placed below and above same.

The accompanying drawings show a preferred nonlimitative embodiment ofthe machine according to the present invention.

FIG. 1 is a diagrammatic axially sectioned view of said machine.

FIG. 2 is a cross-sectional view of 'F IG. 1 taken along the planepassing through AB to illustrate the details of the members controllingthe stepwise movement of the considerable reduction of the cost of thefinished articles.

In particular the machine of the present invention is characterized:

by a turntable stepwise rotating about a central shaft and provided witha plurality of discs carrying the workpieces, said discs beingdistributed at equally spaced angular intervals along the periphery ofsaid turntable, each interval corresponding to astation in which acertain work operation is carried out, the different work operationbeing effected simultaneously on different workpieces; coaxially andexternally to said central shaft there being disposed in succession fromthe inside to the outside: an inner stationary sleeve, an intermediatebush rotating with said turntable and an outer stationary frame;

by main members which intermittently move said turntable to pass fromone working station to the next one in the shortest possible time;

by tool-holding chucks situated in each working station and disposedabove, at the side of and under the periphery of said turntable incorrespondence to each workpiece, said chucks having their workingmovement imparted thereto by groups of peripheral cams (i.e. disposed atthe periphery of the turntable between one station and the next) as wellas by a group of axial cams (i.e. disposed along the axis of theturntable) with possibility of simultaneously operating on the pieceswith at least three chucks for each workpiece-carrying disc, said chuckshaving their axes differently disposed and orientable as a whole over anangle of about 200 turntable carrying the pieces to be worked on.

FIGS. 3, 4 and 5 are detailed axially sectioned views of the samemembers.

FIGS. 6, 7, 8, 9, 10, 11 are views of details of the damping devices forthe means driving the turntable as well as of the tappets and of the tierods.

FIGS. 12 and 13 are details of the device for rotating the discscarrying the grippers holding the workpieces, said discs beingdistributed at the periphery of the turntable.

FIG. 14 is a plan view of the device actuating the main shaft.

FIGS. 15 and 16 are views of an actuating device for the turntable witha direct current motor, the speed of which is electronically controlled.

FIGS. 17 and 18 are views of a mechanical device to increase thedisplacement speed of the turntable.

FIGS. 19, 20, 21 are views ofa rocker arm device for the feeding motionofthe tool-carrying chucks.

FIGS. 22 and 23 are views of a displacement system for the axes of thechucks parallel to themselves, said system being called working centerwith stationary coordinates (also applicable to each chuck).

FIG. 24' is a view of a device applicable to each chuck for thedisplacement thereof along two coordinate axes, a vertical and ahorizontal one.

FIGS. 25, 26, 27 are views of a device enabling the tool of the chuck,to which it is applied, to effect circular motions.

FIG. 28 is a view of a rotating device feeding and straightening the rawwire fed to the machine for obtaining the various finished articles.

FIGS. 29 and 30 are views of a roller device for feeding andstraightening the raw wire horizontally inserted in the self-centeringgrippers.

FIGS. 31 and 32 are views of a device to charge the correspondingself-centering grippers with pressed, stamped, pre-turned or in anyother way pre-shaped rough pieces or blanks.

With reference to the various figures: the main motor 3 (FIG. 1)situated in the base frame 1 drives, by means of a belt speed-varier,the worm wheel 4 and therewith the main shaft 5.

This shaft actuates in its turn, through the toothed wheels 6 and thebevel gears 7, the groups of lateral cams 8 situated outside of eachlateral surface of the hexagonal casing 2 (see FIGS. 2 and 14). Thusthere are six groups of cams 8 distributed in correspondence to eachlateral surface of the hexagonal casing.

Coaxially to the central shaft and externally thereto there are disposedin succession from the inside to the outside:

the stationary inner sleeve 194 (fixed with the base frame 1), theintermediate rotating bush 18 and the outer stationary frame 193. Thisparticular disposition has considerable advantages which will beillustrated later on.

The stepwise rotating turntable 16 is fixed to the intermediate rotatingbush l8 and is intermittently operated by the secondary turntable 9illustrated in FIG. 2, in the following manner:

The first cam 19 which is provided in the secondary turntable 9 actuatesby means of the roller 20 and the levers 21, 22, 23 the centraloscillating lever 24 (see also FIG. 1) which is mounted idle on thecentral shaft 5 so as to impart to said oscillating lever an oscillatoryaccelerated and decelerated motion, the amplitude of which correspondsto the angular displacement which is to be imparted to the stepwiserotating turntable 16.

Noteworthy is the detail of the connection between the levers 22 and 23which takes place over a clickjoint" (FIGS. 4, 5) in the followingmanner: the lever 23 (FIGS. 2, 3) carries at its end a fork member 23'having the slide 191' (FIG. 5) sliding therein. Said slide 191 ispivotedon the lever 22 (FIG. 2) and is connected to the bush 193 (FIG.4) by means of the rod 192. The body 195 (FIG. 4) fixed to the forkmember 23' (FIG. 5) of the lever 23, is resiliently connected to thebush 193 through the balls 194' situated in the holes provided in theabove mentioned body 195. The balls 194 are pushed by the sleeve 190 andby the spring 196 into the groove 193 ofthe bush 193. During the normaloperation of the machine the joint acts as a rigid connection member. Inthe event of ajamming up of the machine, i.e. in case the force requiredto displace the rotating turntable 16 should exceed the normal value,the component of the forces acting through the balls 194' between thebush 193 and the sleeve 190 would overcome the counterforce of thespring 196; the bush 193 would then move with respect to the body 195 sothat the balls would leave the groove 193. As a consequence thereof theforce would then practically fall to zero so as to prevent any damage tothe mechanical parts. During this operation, the sleeve 190 displacesthe block 200 and disconnects the switch 201 which, in its turn, acts onthe emergency brake. By means of the threaded nut 197 it is possible toexactly set the oscillating lever 24 (FIG. 3) so that the piston 25 ispositioned with great precision withrespect to the complementary pins18' protruding from the intermediate bush 18 as it will be betterexplained later on. The clamping device 198 (FIG, 2) is provided fordamping the whole system.

Going back again to FIG. 3: the lever 24 carries the small piston 25which is vertically displaced by the doubleacting cam 26.

By moving upwards, the small piston 25 enters with its conical opening25 into one of the complementary pins 18 protruding from theintermediate rotating bush 18. The double acting cam 26 lifts the smallpiston 25 in the forward moving phase of the oscillating lever 24 andtherefore of the stepwise rotating turntable l6 and lowers the same inthe return phase of the oscillating lever 24.

To increase the operational security of the machine, the small piston 25actuated by the double acting cam 26 is provided with a damping device.Said damping device comprises a cylindrical body 45 (FIGS. 6, 7, 8)pushed upwards by the springs 49 which act on the body itself throughthe small plate 47 and the balls 48 (see the detailed construction inFIG. 7).

During the normal operation of the machine, the cylindrical body 45enters into the conical pins 18' of the sleeve 18 (see FIGS. 1, 3, 6)and, to obtain a perfect tightness without any clearance, saidcylindrical body 45 must resiliently adapt itself to the associated Thecam 26 imparts to the cylindrical body 45 a stroke some tenths of a mm.larger than normal so that the springs 49 also are compressed therebysome tenths of a millimeter.

In case of accidental phase displacement of the machine, the cylindricalbody 45 undergoes an elastic yielding along the whole length of itsprojecting part, without however exerting a force great enough to beharmful to the machine.

In this case, once a certain relative displacement or travel between thecylindrical body 45 and the container 46-46' has been exceeded, theballs are pushed towards the periphery of the container 46-46 while thevertical force on the cylindrical body 45 decreases. A further advantageconsists in that the displacement of the small plate 47 and of thesprings 49 is less than half of the displacement of the cylindrical body45.

The small plate 47 has fixed thereto a pin 47', which actuates in caseof accidental phase displacement the lever 50 which, in its turn;controls the electric contact 51 by means of the magnet 85. The contact51 activates the emergency brake.

During operation the rotating turntable 16 is made stationary by therods 14.

To prevent any breakage of machine elements in case of incorrectfunctioning or blockage of the machine, the tappets controlling the workstations are provided with release damping devices as illustrated inFIGS. 9 and 10, comprising a hollow cylinder 41 and a coaxial stem 42;the balls 40 are pressed in the groove 42 by the sleeve 44 and by thespring 43. The stem 42 stays thus positioned with respect to the hollowcylinder 41. Hence, under the normal working stress the tappet behaveslike a rigid body. Under a stress larger than normal, on the contrary,the balls move outwards displacing the ring 44 and compressing thespring 43. The stem 42 remains therefore free to slide in its axialdirection practically without any strain.

The advantage of the device consists in that, once the maximum allowablestress has been exceeded, the axially acting force practically falls tozero.

With a conventional spring damping device, on the contrary, the stresswould increase proportionally to the displacement.

FIG. 11 illustrates a tie-rod functioning on the same principle.

The rotating turntable 16 with its gripper-carrying discs 17 (FIGS. 12and 13) is so designed and constructed as to permit the fixing of theworking centers each comprising, for instance, up to three chucks withthe associated independent electric motors which may be fixed verticallyabove as well as vertically below the turntable itself. However they mayalso be fixed horizontally or so as to form any angle comprised betweenand 200. The rotating turntable 16 is provided at its periphery with aplurality of holes to contain the gripper-holding discs 17.

Simultaneously with the displacement of the rotating turntable 16, saiddiscs 17 may be rotated through a certain angle while passing from oneworking station to another.

To this end the toothed wheel 32 fixed below the gripper-carryingjdisc17 engages during the rotation of the turntable 16 the toothed segment33 fixed to the machine body, thereby imparting to the gripper-holdingdisc 17 a rotation through a certain angle.

Said angle depends on the number of teeth of the segment 33. By varyingthe number of teeth of the segment 33 is thus possible to vary saidangle.

()bviously the segment .33 is fixed in the interval comprised betweenone working station and the next one only when it is required to rotatethe work piece in the space between said stations. Hence the toothedwheel 32, after that rotation, must be free to move together with therotating turntable 16 without rotating about itself. This is the reasonwhy the last'tooth 33' of the toothed segment 33 is so constructed as tobe lower than the other teeth. Y Furthermore, to facilitate theengagement of the toothed wheel 32 with the segment 33, the part D ofthe wheel 32 is not provided with the teeth which would precede theteeth 32' providing for the engagement with the toothed segment 33.

To ensure a perfect positioning, before starting the work operations,the gripper-carrying discs 17 are blocked relative to the rotatingturntable 16 by means of the rods 15 (see also FIG. 1).

The rods serving to block the discs 17 and the rods 14 serving to blockin the desired positions the rotating turntable 16 are controlled by thecam 10 fixed to the secondary turntable 9 fixed, in its turn, to themain shaft (FIG. I). The double acting (in both directions) cam 10controls the disc 13 through the rollers 11 and the rods 12. Said dischas fixed thereto a certain number of said rods 14, 15 which, by movingupwards, fix or set the position of the rotating turntable l6 and of thegripper-carrying discs 17, as mentioned above.

A very important detail which constitutes one of the fundamentalcharacteristics of the machine according to the present invention isconstituted by the fact that rods 14 block very firmly and rigidly therotating turntable 16 by passing though the outer stationary frame 193,through the inner stationary sleeve 194 as well as through theintermediate bush 18 rotating together with the turntable. To avoid anyplay, the rods 14 (and 15) move axially, penetrating into bushesprovided with ball rings which are resiliently compressed by the rods.

The control of the working centers is effected by the already mentionedgroups of cams 8 disposed at the side of thehexagonal frame and actingby means of tappets, as well as by the groups of cams fixed to the upperend of the central shaft (see FIG. 1).

With regard to this point it should be noted that the ratio of the gearpairs 6, 7 are so chosen that the shafts carrying the groups of cams 8have a ratio 1/1 with respect to the central shaft 5 and furthermore sothat the number of teeth of the central bevel gear 7 is a multiple ofthenumber of cam groups so as to allow for a ready phase setting.

By means of the modified device illustrated in FIG. 14 it is possible toaccelerate the displacements of the rotating turntable 16.

The main motor 3 (see also FIG. 1) actuates, through a speed varier, theshaft 27 which, in its turn, actuates the shaft with the helical gear 4,through the electromagnetic coupling 28.

The shaft 27 carrying the helical gear 4 is furthermore provided with anelectromagnetic brake 29.

The shaft with the helical gear 4. has coupled to its other end, througha further electromagnetic coupling 30, another motor 31.

By connecting the coupling 28, the main shaft 5 is actuated by the mainmotor 3 while, by connecting the electromagnetic coupling 30, the shaft5 is actuated by the motor 31.

The coupling 29-is connected to block the shaft 5 in case of emergencystopping.

It obviously appears that, by means of this device, the shaft 5 canrotate at two speeds: a first speed :1 imparted by the motor 3 andvariable by means of the varier, and a second speed n imparted by themotor 31.

It is thus possible to vary the working time (i.e. the time during whichthe rotating platform 16 (FIG. 1) is made stationary and the workingmembers effect the working operations) while maintaining constant (andminimal) the time for the displacement of the rotating platform from oneposition to the other.

The connection of the electromagnetic couplings is controlled by acontactor which in its turn is controlled by one of the cams 8.

According to another modification of the above mentioned device, use maybe made of a single direct current motor with electronic speed control,as illustrated in FIGS. 15 and 16.

For passing from one speed n to another speed n it is necessary tocommutate the reference potentials, i.e. the potentials relative to thespeeds, by means of electric or electronic contacts controlled by one ofthe cams 8.

The rapid change from one higher speed n to a lower speed n may beobtained by means of a dynamic braking process according to which thedirect current motor acts as a generator until the speed n has beenreached.

The circuit is diagrammatically represented in FIG. 16. The motor 52 hasa generator tachometer 53 coupled thereto which produces a potentialwhich is directly proportional to the number of revolutions of themotor. The rotational speeds are preselected by means of thepotentiometers 54, 55. A commutator 63, controlled by one of the cams 8,effects first one and then the other of the preselected speeds.

The electronic circuit 64 comparesthe potential of the tachometer withthe potential of the inserted potentiometer and controls, as a functionof said potentials,

1. A machine for high speed, extremely precise mass production of pieceshaving small dimensions and complex forms, characterized: by a turntable(16) stepwise rotating about a central shaft (5) and provided with aplurality of discs (17) carrying the workpieces, said discs beingdistributed at equally spaced angular intervals along the periphery ofsaid turntable, each interval corresponding to a station in which acertain work operation is carried out, the different work operationsbeing effected simultaneously on different workpieces; coaxially andexternally to said central shaft (5) there being disposed in successionfrom the inside to the outside; an inner stationary sleeve (194), anintermediate bush (18) rotating with said turntable (16) and an outerstationary frame (193); by main members to intermittently move saidturntable to pass from one work station to the next one in the shortestpossible time; by tool-holding chucks situated in each work station anddisposed above, at the side and under the periphery of the turntable incorrespondence to each workpiece, said chucks having their workingmovement imparted thereto by groups of peripheral cams (8) disposed atthe periphery of the turntable between one station and the other as wellas by a group of axial cams (95) disposed along the axis of theturntable, with possibility of simultaneously working the pieces with atleast three chucks for each workpiece-carrying disc, saId chucks havingtheir axes differently disposed and orientable as a whole through anangle of about 200* and fixable to the outer stationary frame (193)coaxial to the central shaft (5); by means to exactly fix with greatrigidity the position reach by the turntable at each work station beforestarting the work operation, said fixing being obtained by engaging andfirmly holding said stationary inner sleeve (194) as well as saidexternal stationary frame by secondary members to displace angularly toitself the axis of each workpiece-carrying disc so as to bring the sameinto the right working position and means to fix the same in the exactposition before starting the work operation; said discs being shaped forworking with chucks placed below and above the same.
 2. The machine asclaimed in claim 1, characterized in that said main members tointermittently move said turntable to pass from one station to the nextone comprise a main motor (3) driving, by means of a speed varier, aworm wheel (4) and therewith the main shaft (5) coaxial and idle withrespect to said turntable (16), said central shaft (5) carrying, fixedcoaxially thereto, a secondary turntable (9) profiled as a cam (19) soas to operate, with intermittent accelerated and decelerated motion andthrough a lever system (21, 22, 23), a central oscillating lever (24)which is also coaxially and idly mounted on said central shaft (5), saidcentral oscillating lever (24) carrying, in its turn, an engaging member(25) provided with complementary means (18'') situated at the base ofthe intermediate rotating bush (18) coaxially fixed to the abovementioned turntable (16); the engaging and disengaging of said members(18'', 25) being controlled by a double acting cam (26) fixed to thecentral shaft (5); said double acting cam being profiled so as toenable, during the angular displacement phase of the central oscillatinglever (24), the engagement with the intermediate rotating bush (18) andtherefore with the turntable (16) during rotation thereof and thedisengagement therefrom during the return phase of said oscillatingcentral lever (24).
 3. The machine as claimed in claim 1, characterizedin that said system of levers (21, 22, 23) actuate said centraloscillating lever (24) over a click-joint comprising a fork member(23'') situated at the end of the lever (23) directly connected to thecentral oscillating lever (24), said fork member 23'' having a slidemember (191) sliding thereon, pivoted to the preceding lever (22) andfixed to a bush (193) having an annular groove (193'') containing balls(194'') situated in holes in a body (195) coaxially placed outside ofsaid bush (193), said body being axially subjected to stresses by aspring (196); the whole being so designed and constructed that duringthe normal functioning of the machine the joint behaves as a rigidconnection while, in case of excessive stresses required to angularlydisplace the rotating platform (16), the action of said spring isovercome, the balls come out of said annular groove (193'') therebyreleasing the bush (193) from the body (195) preventing stress frombeing transmitted to the central oscillating lever (24) which, in itsturn, is connected to the members driving the rotating turntable (16) byway of a damping device (198).
 4. The machine as claimed in claim 1,characterized in that said engagement member (25) is made to slidewithin a container (46) and is subjected to elastic stresses by springs(49); said engagement member (25) and said container comprisingthere-between the seat for a ball (48) adapted, under normal workingconditions, to rigidly connect said two members and, under an axialstress higher than normal, to move radially so as to permit a reciprocalaxial sliding motion.
 5. The machine as claimed in claim 4,characterized in that one or the other of said complementary engagementmembers (19'', 25'') are cushioned.
 6. The machine as claimed in claim1, characterized in that to prevent the machine members from breaking incase of incorrect functioning of the machine, tappets acting on saidperipheral cams (8) and on said axial cams (95) are provided withdamping or cushioning devices, each constituted by two coaxial partssliding one in the other (41, 42), one part (41) consisting of a hollowcylinder provided with a ball (40), the other part consisting of acoaxial stem (42) provided with a groove (42'') having entering thereinsaid ball pushed by a sleeve (44) subjected to elastic stresses by aspring (43), the whole being so designed that under an excessive stressthe ball enters into the recess thereby enabling the stem (42) to slideinto the hollow cylinder (41).
 7. The machine as claimed in claim 1,characterized in that the secondary members to angularly displace theaxis of each disc (17) so as to bring same into the right workingposition are constituted by a toothed wheel (32) fixed coaxially undereach disc and by a toothed segment (33) coaxial with the central shaft(5) of the machine and fixed to the base frame; said toothed segment(33) having at regular intervals, between one work station and the nextone, at least a tooth (33'') which is lower than the others so as topermit the angular displacement of the disc driven by the turntable (16)without any of its own rotation, whereby the angular displacement of thedisc passing from one working station to the next one may be varied byvarying the number of teeth of the toothed segment (33) with respect tothe number of teeth of the above mentioned toothed wheel (32).
 8. Themachine as claimed in claim 1, characterized in that the position of theturntable (16) and the one of the workpieces-carrying discs (17) isfixed in correspondence to each working station by means of blockingrods (14, 15) carried by a disc (13) actuated by a double acting cam(10) fixed to a secondary turntable (9) fixed to the central shaft (5);said blocking rods passing through holes in the stationary part of themachine and holes in the step wise rotating turntable (16).
 9. Themachine as claimed in claim 1, characterized in that the groups ofperipheral cams (8) and the group of axial cams (95) are operated by apair of bevel gears (7), the pair fixed to the central shaft (5) havinga number of teeth which is a multiple of the one driving the peripheralcams (8) according to the number of work stations so as to readilypermit the phase setting of the machine.
 10. The machine as claimed inclaim 1, characterized by members to facilitate the acceleration and thedeceleration of the rotating turntable (16) comprising: a firstelectromagnetic coupling (28) by way of which the central shaft (5) isactuated by the main motor (3) over a speed variator; a secondelectro-magnetic coupling (30) by way of which the central shaft (5) isdriven by an auxiliary motor (31) having a speed (n2) which is differentfrom that of the main motor (n1) while an additional coupling (29)serves to stop the central shaft (5) in case of an emergency; theconnection of said electromagnetic coupling being controlled by acontactor through the group of peripherical cams (8).
 11. The machine asclaimed in claim 1, characterized by members to control the rotatingturntable (16) with two different speeds which are adjustable by meansof a direct current motor the speed of which is electronicallycontrolled a generator-tachometer (53) generating an electric potentialwhich is directly proportional to the number of revolution of the motor,the rotary speeds of the rotating turntable being preselected by meansof two potentiometers (54, 55) while a commutator (63) driven by one ofthe lateral cams (8) inserts one or the other of the preselected speeds;a braking circuit, in which the motor is used as a generator, for therapid change from one speed to the other, while an electromagnetic brakeis provided for emergency stopping.
 12. The machine as claimed in claim1, characterized by a meChanical device to facilitate the accelerationand deceleration of the rotating turntable (16) by increasing thedisplacement speed thereof from one work station to the next one, saiddevice being characterized by an inner body (194) fixed to the centralshaft (5) and having radial holes with pistons (101) sliding therein,said pistons being stressed outwards by springs (102), and having fixedthereto rollers (104) which slide along concave surfaces (105) providedin the cylinder (18) in a number equal to that of the work stations ofthe turntable (16), said concave surfaces being disposed in such a waythat, when the turntable stands still during the work operation, therollers (104) are in the highest region of said concave surfaces while,during the displacement phase of the turntable, they are in the lateralor central region of said concave surfaces.
 13. The machine as claimedin claim 1, characterized by rocker arm devices to control thedisplacement of each tool-carrying chuck; each device comprising a lever(117) actuated by a tappet (116) receiving the motion from a control cam(8), said lever (117) acting on a pivot (118) to transmit the motion byway of a profiled pawl (70) to two coaxial and polygonal lateral bushes(71, 71'') one of said bushes actuating a lateral arm (94), the otheractuating another lateral arm (94'') each placed at one side of achuck-actuating motor (98); said pawl being so profiled as to have twogrooves (70'', 70'''') defining a central protruding portion acted uponby the driving force whereby the same is distributed in balanced manneron each of said two arms, placed at one side of the motor.
 14. Themachine as claimed in claim 1, characterized by devices to displace theaxis of each chuck parallel to itself within a given area for to workpieces with complicated forms, each device comprising two bushes withparallel axes (73, 74) eccentrically disposed one within the other andangularly displaceable by means of a gear control unit (75, 76); theinner bush being adapted to receive axially slidable therein on ballsthe motor (98) carrying the corresponding chuck.
 15. The machine asclaimed in claim 1, characterized by devices applicable to the variouschucks to permit the displacement thereof along two axes, a vertical anda horizontal one, each device comprising a frame (130) having fixedthereto the preselected chuck (99), said frame being slidable alonghorizontal guides (131) with the control coming from one of theperipheral cams (8) by way of a roller (133) and a lever (132), thecombination of members forming the frame (130) and the guide (131) beingadapted to slide vertically along vertical guiding columns by means of asecond cam of the peripheral group (8) and of a central lever (136);said frame (130) being adapted to be fixed to the vertical columns (135)by means of a gauge member when its displacement along the coordinateaxes is not required.
 16. The machine as claimed in claim 1,characterized by devices enabling the various tools to effect circularmotions, each device comprising a bush (136) with an eccentric guidinghole (136'''') for the corresponding chuck (98); said bush (136) beingprovided at its periphery with a toothed wheel (136'') engaging acomplementary toothing (137) of a wheel actuated by way of a shaft (141)by a second toothed wheel (138) which is driven by a rack (139) set intomotion by a lever (140) driven by way of a tappet by one of the cams ofthe peripheral group (8) (FIG. 1); whereby said chuck (98) may alsoeffect contemporaneously a vertical displacement by way of a secondlever (142) actuated by one of the cams of the axial group (95).
 17. Themachine as claimed in claim 1, characterized by a device feeding andstraightening raw wire coming from a supply of wire, said devicecomprising a frame (145) set into rotation by the main shaft (5) of themachine; said frame carrying at least three bushes (148), the centralone of which is eccentric with respect to the twO others and also withrespect to the rotational axis, the eccentricity being variableaccording to the diameter of the wire and the type of material; saidframe being adapted to perform simultaneously also an intermittent axialdisplacement controlled by a cam (149) by means of a rod (150) and alever (151), the wire being fed axially with a speed which is largerthan that of the axial displacement of the above mentioned frame so thatthe wire is straightened also during the axial return motion of saidframe.
 18. The machine as claimed in claim 1, characterized by a devicefor horizontally feeding wire comprising a slide (167) having two levers(168, 168'') pivoted thereon and pushed by two springs (169, 169''),said levers firmly holding the previously straightened wire during theforward travel of the slide and releasing said wire during the returntravel of the same; said slide being driven by way of a lever (170) by atappet-cam (171); a milling tool (173) also actuated by way of atappet-cam (174) cutting the wire once the same has been introduced intothe corresponding self-centering gripper.
 19. The machine as claimed inclaim 1, characterized by a device to introduce in the chucks pressed,pre-turned, stamped or otherwise pre-profiled raw pieces or blanks, saiddevice comprising a piston (176) axially driven by a lever (177)actuated by a cam of the axial group, a rotary motion about its axisbeing imparted to said piston by way of a toothed wheel (179) and a rack(178) actuated by a second cam of the axial group (95), said pistoncarrying at its lower end a square shaped member (180), the ends ofwhich have pivoted thereto two pairs of jaws (181, 181'') held in closedposition by springs (182, 182''), whereby said jaws may be opened by arod (183) with a conical lower end portion (183'') coaxial to saidpiston (176) and driven by a mechanism (184) with a cam (200) and atappet (185); a pair of said jaws serving to clamp the finished piece(187) and the other clamp a blank (186); the lifting and successiverotation through 90* of said square shape member (180), after thefinished piece has been disengaged from the corresponding self-centeringgripper (169), permitting the discharge of the finished piece and theintroduction of a new blank in said self-centering gripper (179).